Wire joining tool

ABSTRACT

A hand held, motor driven, wire joining tool is disclosed which includes two wire gripping jaws adapted to twist wires gripped therein by counter-rotating with respect to each other and a heater for melting insulation from the wires as they are twisted.

United States Patent Cushman WIRE JOINING TOOL [72] Inventor: RobertHolbrook l-luntingdon Valley, Pa.

[73] Assignee: Western Electric Company, Incorporated, New York, NY.

[22] Filed: Dec. 22, 1970 [21] App1.No.: 100,660

Cushman,

[52] US. Cl ..140/l11, 140/119 [51] Int. Cl. ..B2lf 15/04 [58] Field ofSearch ..140/1l8,l19,122,123,124,

[56] References Cited UNITED STATES PATENTS Suzuki ..l40/1 19 1 Oct. 24,1972 Primary Examiner-Jnwell A. Larson Attorney-R. J. Guenther and EdwinB. Cave 5?] ABSTRACT A hand held, motor driven, wire joining tool isdisclosed which includes two wire gripping jaws adapted to twist wiresgripped therein by counter-rotating with respect to each other and aheater for melting insulation from the wires as they are twisted.

14 Claims, 3 Drawing Figures PATENTEDncr 24 I972 3 700.009

' sum 1 OF 3 Uv l ENYTOR R. H. CUSHMAN A TTORNEV WIRE JOINING TOOLBACKGROUND OF THE INVENTION 1. Field of the Invention This inventionrelates to wire joining techniques and pertains in particular toapplications in which the wires to be joined are covered by a layer ofinsulation.

2. Description of the Prior Art In the telephone industry, the functionof connecting, disconnecting and reconnecting wires is a never endingprocess. Since all three operations occur in huge numbers, the smallesteconomies in any one can produce large cost savings.

I-Ieretofore, connections have typically been made in two steps; i.e.,first insulation is stripped away and then the exposed wires are twistedto form a mechanical bond. By reducing the number of steps in theconnecting process, workmen will find their task easier and'efficiencycan thus be improved. In this manner, cost economies can readily beachieved.

Accordingly, one object of this invention is to simplify the process ofjoining wires together.

The connected wires are typically tool joined and, where the insulationis stripped'prior'to. joining, more than one tool is usually required.For example, a knife or other stripping tool is ordinarily used toremovethe insulation and a twisting tool such as pliers or the like isused to intertwine the exposed wires. While separate stripping andtwisting tools generally give satisfactory results, multiple toolsincrease inventory. Moreover, tool losses occur and the inconvenienceinherent in the use of two tools can readily decrease operatorefficiency. Such drawbacks, however, can be overcome if the functionsperformed by the separate tools are combined into a single multi-purposetool.

Accordingly, another object of this invention is to combine thefunctions of insulation stripping and wire twisting in one tool.

Additionally, if the single tool can perform both functionssimultaneously, the operator's task will be simpler and easier toperfomi.

Accordingly, another object of this invention is to achieve simultaneousinsulation stripping and wire twisting in a single tool.

In order to make a firm connection, the union between the wires must betight and strong. While wrapping the wires tightly usually gives goodresults, it is better if the wires can be bonded to each other as well.

Accordingly, another object of this invention is to achieve bonding ofthe wires during the twisting and insulation stripping operation.

SUMMARY OF THE INVENTION In accordance with this invention, two or moreparallel insulated wires are stripped of their insulation whilesimultaneously being twisted together to form either a mechanical bondor a true fusion or thermal compression bond.

According to one feature of this invention, simultaneous insulationstripping and wire twisting is achieved by applying heat to the wires asthey are twisted so that melted insulation is squeezed from between thewires to expose bare metal.

According to another feature of this invention, a wire joining tool forstripping insulation from wires and twisting the wires to form aconnection comprises two jaws for twisting asegment of wires grippedtherein, a support'holding' the two jaws, and a'heater for applying'heat to the segment gripped in the two jaws.

According to another feature of this invention the heater applies heatto the insulation of the wires as they are being twisted by thejaws'whereby the insulationwhich portions are broken away to showdetails;

FIG. 2 is a partial plan view of the wire joining tool shown in FIG. 1and has portions broken away to show details; and

FIG. 3 is an elevation view of the wire joining tool shown in FIG. 2taken along the lines 3--3 and has portions broken away to show detailsand includes an alternate heating arrangement.

DETAILED DESCRIPTION Referring to FIG. 1, a wire joining tool isdisclosed which comprises a shaft 10, a collar 11, a handle 12, jaws 13,jaws 15, a sleeve 14 and a linkage 17. The illus- "trated tool is ahand-held device in which all of the foregoing components cooperate tosimultaneously strip insulation from and twist two or more wires into aelectrical and mechanical connection.

The shaft 10 is cylindrical and, as best seen in FIG. 3, one endincludes a hole which is tapped to accommodate a threaded member. Theother end is attached to a motor (not shown) which may conveniently bemountedon-the handle 12 and which is adapted to impart rotational motionto the shaft 10 when actuated. The shaft 10 is advantageously made ofstainless steel alloy and, asbest seen in FIGS. 1 and 3, includes agroove to accommodate one or more conductor leads 16. While notexplicitly shown, one of the conduction leads 16 is connected at one endto a current source (not shown) through a switch 18 in the handle 12 ina conventional manner and has its other end connected to the jaws 13.Similarly, another conductor lead 16 extends from the jaws 13 to theother end of the current source to complete an electrical circuit.

The collar 11 comprises a face block 20 having a hole of sufficientlylarge diameter to slidably accommodate the shaft 10. In addition, itincludes two projecting ears 21 and four projecting pins 22. As shown inFIGS. 1 and 3, the ears 21 cooperate with moving parts in the handle 12.Advantageously, the face block 20 is made of a material such asstainless steel.

The handle 12 comprises the aforementioned switch 18, a grip 24 and atrigger 25 mounted on a pivot 28. The grip 24 is conveniently made of anelectrically nonconducting material such as phenolic, and the switch 18and the pivot 28 are advantageously mounted therein. As best seen inFIG. 2, two ears 26 project from the end of the trigger 25 and arecoupled to the ears 21 on the collar 11 by connecting pins 27 so thatthe face block 20 will slidably reciprocate on the shaft in response torotation of the trigger 25 about the pivot 28.

As best shown in FIG. 3, the switch 18 is activated in response torotational movement of the trigger 25. When actuated, it closes anelectrical circuit (not shown) so that current will flow through the twoleads 16 which are electrically connected to the jaws in a conventionalmanner.

As illustrated best in FIG. 3, the jaws 13 comprise two elongated legs30 separated by an end support 31. As shown in FIG. 3, the end support31 is threaded so as to screw into the tapped hole in the end of theshaft 10. Consequently, when the end support 31 is screwed into thehole, the jaws 13 will rotate when the shaft 10 rotates.

The legs 30 are adapted to flex at the point of juncture with the endsupport 31 and are made of a material such as inconel 718. The outerside of each leg 30 includes a cam surface 32 which, when subjected to acompression force, will urge the two legs 30 toward one another so as togrip a wire or wires inserted therebetween. As shown in FIG. 3, eachconductor lead 16 is attached to one of the two legs 30 so that currentflowing therethrough will cause the jaws 13 to be heated.

- The sleeve 14, as can be seen from FIG. 3, is hollow along its longaxis so as to slidably accommodate the shaft 10. It has a shoulder 38 atone end and two cam surfaces 36 at the other end. The cam surfaces 36are adapted to engage the cam surfaces 32 on the jaws 13 and to compressthe jaws 13 in response to pressure exerted by the sliding movement ofthe collar 11. The sleeve 14 may advantageously be made of a materialsuch as stainless steel.

The sleeve 14 also includes a slot 37 adapted to accommodate a pin 39.As shown in FIG. 3, the pin 39 is inserted in the side of the shaft 10so as to limit the sliding movement of the sleeve 14 thereon.

As best seen from FIGS. 2 and 3, the jaws 15 include two facing clampingplates 40. Each clamping plate 40 advantageously contains groove 41 foraccommodating two or move wires during the clamping process and extendstranversely between the ends of the two arms 45. For convenience, theclamping plates 40 can be made of stainless steel to retard heatconduction.

As illustrated in FIGS. 1 and 2, the arms 45 are part of a linkage 7 andmay be made of stainless steel. Each arm 45 includes a slot 47 at oneend. Moreover, each is attached to a clamping plate 40 at the other endand is joined to an adjacent arm 45 by a centrally located pivot pin 46.Both pivot pins 46 are held stationary with respect to the shaft 10 by apair of brackets 48 which, as best seen in FIG. 2, are rigidly fastenedto the grip 24 but which are advantageously electrically insulated fromthe grip 24 by use of insulation such as washers or spacers made out ofpolyimide or equivalent insulating material. As a result, the jaws 15are unable to rotate as are the jaws 13. The slots 47, as best seen inFIGS. 1 and 2, are filled by the pins 22 which rotate the arms 45 aboutthe pivot pins 46 in response to the reciprocal movement of the faceblock as it slides on the shaft 10 and thereby cause the jaws 15 to openand close.

The jaws 15 may include, if desired, two insulation collecting cups 50.As shown in FIGS. 2 and 3, the two cups 50 cooperate with each other toaccumulate insulation melted from wires being twisted together by thejaws 13 and 15.

In operation, two or more wires are inserted, as shown in FIG. 1,through the jaws 15 in parallel with each other and into the jaws 13.Thereafter, the trigger 25 is actuated to slide the collar 1 1 forwardon the shaft 10. As the collar 1 1 slides, it simultaneously rotates thearms 45 and pushes the sleeve 14 forward. The rotational movement of thearms 45 closes the jaws 15 against the wires at one point and thesliding movement of the sleeve 14 presses the cam surfaces 36 againstthe cam surfaces 32 and thereby closes the jaws 13 against the wires atanother point.

As the trigger 25 continues to move, it actuates the switch 18 tosimultaneously energize the motor (not shown) and close a circuitleading from a low voltage, high current source such as a stepdowntransformer, for example (not shown). The leads 16 are connected to thelow voltage source so that current will pass serially through the jaws13 when the circuit is closed.

With the circuit closed, current will continue to flow until the jaws l3become heated and the insulation on the wires begins to soften and evenmelt. If desired, heating is continued until the metal in the wiresreaches wire bonding temperature. As the insulation softens and melts,it is squeezed out between the twisted wires and is trapped in the cups50 where it is retained until the twisting operation is complete.

As the insulation is softening or melting, the motor (not shown), isrotating the shaft 10. As a consequence, the jaws 13 are also rotatingand the segment of wires located between the jaws 13 and 15 is beingtwisted.

Twisting creates a tensile stress on the segment of the wires betweenjaws l3 and 15 which continues until breakage occurs. As heat is appliedto the wires from the jaws 13, the portion nearest the jaws 13 becomeshottest. Consequently, that portion will be the weakest pointstructurally in the segment. As a result, when the wires break, therupture will occur just beyond the tips of the jaws 13. The resultingconnection, therefore, will ordinarily have a neat, clean appearance.Moreover, the magnitude of force which must be reached in order toobtain rupture will automatically cause the heated, unbroken wires inthe segment to be joined by a fusion or compression type bond.

The connection or union between the wires is completed by releasing thetrigger 25. When the trigger 25 is released, the jaws 13 and 15 open andallow the connected wires to be withdrawn. If the jaws 15 include cups50, the joined wires will be pulled through melted insulation as theyare withdrawn. As a result, the melted insulation will be rewiped backonto the exposed surfaces of the wires thereby producing a joint whichnot only has good mechanical and electrical properties, but which willalso be covered with insulation. Advantageously, the motor can be madeto rotate against a spring load in a conventional manner when it isenergized. As a result, a number of turns made by the jaws 13 canreadily be controlled, for example, full twisting of the wire segmentcan readily be made to coincide with full rotation of the jaws 13. Insuch a case, the spring loading can readily be used to untwist the jaws13 and return them to the initial position. Where this arrangement isused, the leads 16 need only be long enough to continue wrapping untilthe jaws 13 have fully rotated.

While electric heating is particularly convenient, other forms ofheating can also be utilized. It is essential only that the temperatureof the segment of the wires be raised to a level sufficient to melt theinsulation so that a good metal-to-metal contact can be achieved. Whereelectric heating is used, temperature is readily controlled merely byadjusting the amount of current applied. It has been discovered thatadjusting the temperature to a level in the range of 500 to l500Fahrenheit will produce bonds of good quality.

As an alternate, a cartridge heater 60 can be used as the mechanism forsupplying heat to the jaws l3 and the wire segment gripped therein. Asshown in FIG. 3, the sleeve 14 has a shoulder at one end over which thehollow cartridge heater 60 can slide. When the cartridge heater 60 isused, the leads 16 are connected to the cartridge leads instead of thethe jaws 13. In either case, however, heat can be supplied in responseto pulses or a continuous flow of current.

In summary, a single tool for joining two or more wires bysimultaneously twisting and heating the portions to be connected hasbeen disclosed. It will be understood, however, that the embodimentdisclosed herein merely embodies the principles of the invention andthat other embodiments falling within the scope of the invention willreadily occur to those skilled in the art.

What is claimed is: l. A wire joining device for uniting the free endsof two or more insulated wires comprising:

a pair of jaw means for gripping the opposite ends of a segment of saidwires;

means for rotating one of said jaw means with respect to the other so asto twist said segment; and

heater means for melting insulation from wires in said segment when saidsegment is being twisted by said jaw means whereby said wires will besimultaneously stripped of insulation and twisted into a mechanicalconnection, said heater means including a source of electric current,conductor means for connecting said pair of jaw means to said source ofelectrical current and means for interruptably allowing current to flowserially through one of said jaw means, a segment of wires gripped insaid one jaw means and the other of said jaw means when said jaw meansare twisting said segment of wires.

2. A wire joining tool for uniting the free ends of two or moreinsulated wires comprising:

a rotatable sh aft;

means for rotating said shaft;

a collar slidably mounted on said shaft;

handle means for sliding said collar back and forth on said shaft;

first jaw means for holding said wires together in parallel at onepoint, said first jaw means being rigidly attached to said shaft so asto rotate when said shaft rotates;

sleeve means for opening and closing said first jaw means in response toreciprocal movement of said collar on said shaft, said sleeve meansbeing slidably mounted on said shaft;

second jaw means for holding said wires together in parallel at anotherpoint;

means for removing insulation from wires gripped in said first andsecond jaw means when said shaft is rotated; and

linkage means for opening and closing said second jaw means in responseto reciprocal movement of said collar on said shaft and for holding saidsecond jaw means fixed with respect to rotational movement of said shaftwhereby wires gripped by said first and second jaw means will besimultaneously stripped of insulation and twisted when said shaft isrotated.

3. A wire joining tool in accordance with claim 2 wherein said first andsecond jaws are electrically insulated from each other, and said meansfor removing insulation is a heater for melting insulation on saidwires.

4. A wire joining tool in accordance with claim 3 wherein said heaterincludes means for applying an electrical current serially through saidfirst jaw means, wires gripped in said first and second jaw means andsaid second jaw means when said wires are being twisted.

5. A wire joining tool in accordance with claim 2 wherein said first jawmeans includes two elongated jaws and first cam surfaces on each of saidjaws for closing said jaws when subjected to a compressive force, andsaid sleeve means includes second cam surfaces for applying acompressive force to said first cam surfaces in response to slidingmovement of said collar on said shaft.

6. A wire joining tool in accordance with claim 5 wherein said twoelongated jaws have a common threaded end support and said shaftincludes a tapped hole for accommodating said threaded end support.

7. A wire joining tool in accordance with claim 2 wherein said linkagemeans includes a pair of arms centrally joined to each other by a pivotpin and camming pins for imparting reciprocal rotation to said armsaround said pivot pin in response to reciprocal sliding movement of saidcollar on said shaft, and said second jaw means includes two opposedjaws attached to said arms and arranged to grip and release wiresinserted therebetween in response to reciprocal rotation of said armsabout said pivot pin.

8. A wire joining device in accordance with claim 7 wherein said secondjaw means includes spreading means for coating said wires with meltedinsulation as said wired are removed from said two opposed jaws.

9. In a wire joining method for uniting two or more parallel insulatedwires in which the wires are initially held in fixed relationship toeach other at two separate points, the step of applying heat to segmentsof said wires lying between said points while simultaneously twistingsaid segments together whereby heated insulation is squeezed frombetween adjacent twisted wires and a metal-to-metal bond is formedhaving great mechanical strength and good electrical conductivity.

10. A wire joining method in accordance with claim 9 wherein said heatis applied until said insulation melts sufficiently to expose bare metalon adjacent surfaces of said wires whereby extensive metal-to-metalcontact is established between adjacent wires.

11. In a wire joining method in accordance with claim 10, the additionalstep of spreading melted insulation back over the exposed bare metal ofsaid wires after said bond is formed to reinsulate said wires.

12. A wire joining method in accordance with claim 9 wherein said heatis applied until said wires reach bonding temperature whereby the wiresreadily deform cross-sectionally during twisting and a good electricalunion is formed between adjacent wires.

13. A wire joining method in accordance with claim 12 wherein twistingis continued until the wires rupture.

14. A wire joining method in accordance with claim 12 wherein heatapplied to said wires falls in the range of 500 to 1,500 Fahrenheit.

1. A wire joining device for uniting the free ends of two or more insulated wires comprising: a pair of jaw means for gripping the opposite ends of a segment of said wires; means for rotating one of said jaw means with respect to the other so as to twist said segment; and heater means for melting insulation from wires in said segment when said segment is being twisted by said jaw means whereby said wires will be simultaneously stripped of insulation and twisted into a mechanical connection, said heater means including a source of electric current, conductor means for connecting said pair of jaw means to said source of electrical current and means for interruptably allowing current to flow serially through one of said jaw means, a segment of wires gripped in said one jaw means and the other of said jaw means when said jaw means are twisting said segment of wires.
 2. A wire joining tool for uniting the free ends of two or more insulated wires comprising: a rotatable shaft; means for rotating said shaft; a collar slidably mounted on said shaft; handle means for sliding said collar back and forth on said shaft; first jaw means for holding said wires together in parallel at one point, said first jaw means being rigidly attached to said shaft so as to rotate when said shaft rotates; sleeve means for opening and closing said first jaw means in response to reciprocal movement of said collar on said shaft, said sleeve means being slidably mounted on said shaft; second jaw means for holding said wires together in parallel at another point; means for removing insulation from wires gripped in said first and second jaw means when said shaft is rotated; and linkage means for opening and closing said second jaw means in response to reciprocal movement of said collar on said shaft and for holding said second jaw means fixed with respect to rotational movement of said shaft whereby wires gripped by said first and second jaw means will be simultaneously stripped of insulation and twisted when said shaft is rotated.
 3. A wire joining tool in accordance with claim 2 wherein said first and second jaws are electrically insulated from each other, and said means for removing insulation is a heater for melting insulation on said wires.
 4. A wire joining tool in accordance with claim 3 wherein said heater includes means for applying an electrical current serially through said first jaw means, wires gripped in said first and second jaw means and said second jaw means when said wires are being twisted.
 5. A wire joining tool in accordance with claim 2 wherein said first jaw means includes two elongated jaws and first cam surfaces on each of said jaws for closing said jaws when subjected to a compressive force, and said sleeve means includes second cam surfaces for applying a compressive force to said first cam surfaces in response to sliding movement of said collar on said shaft.
 6. A wire joining tool in accordance with claim 5 wherein said two elongated jaws have a common threaded end support and said shaft includes a tapped hole for accommodating said threaded end support.
 7. A wire joining tool in accordance with claim 2 wherein said linkage means includes a pair of arms centrally joined to each other by a pivot pin and camming pins for imparting reciprocal rotation to said arms around said pivot pin in response to reciprocal sliding movement of said collar on said shaft, and said second jaw means includes two opposed jaws attached to said arms and arranged to grip and release wires inserted therebetween in response to reciprocal rotation of said arms about said pivot pin.
 8. A wire joining device in accordance with claim 7 wherein said second jaw means includes spreading means for coating said wires with melted insulation as said wired are removed from said two opposed jaws.
 9. In a wire joining method for uniting two or more parallel insulated wires in which the wires are initially held in fixed relationship to each other at two separate points, the step of applying heat to segments of said wires lying between said points while simultaneously twisting said segments together whereby heated insulation is squeezed from between adjacent twisted wires and a metal-to-metal bond is formed having great mechanical strength and good electrical conductivity.
 10. A wire joining method in accordance with claim 9 wherein said heat is applied until said insulation melts sufficiently to expose bare metal on adjacent surfaces of said wires whereby extensive metal-to-metal contact is established between adjacent wires.
 11. In a wire joining method in accordance with claim 10, the additional step of spreading melted insulatiOn back over the exposed bare metal of said wires after said bond is formed to reinsulate said wires.
 12. A wire joining method in accordance with claim 9 wherein said heat is applied until said wires reach bonding temperature whereby the wires readily deform cross-sectionally during twisting and a good electrical union is formed between adjacent wires.
 13. A wire joining method in accordance with claim 12 wherein twisting is continued until the wires rupture.
 14. A wire joining method in accordance with claim 12 wherein heat applied to said wires falls in the range of 500* to 1,500* Fahrenheit. 